Strippable wax coating compositions



United States Patent 3,518,215 STRIPPABLE WAX COATING COMPOSITIONS Dominic A. Apikos, Laurel Springs, N.J., assignor to Atlantic Richfield Company, Philadelphia, Pa., a corporation of Pennsylvania No Drawing. Filed June 10, 1966, Ser. No. 556,555 Int. Cl. C08f 45/44, 45/52 US. Cl. 26028.5 1 Claim ABSTRACT OF THE DISCLOSURE This invention relates to strippable wax coating compositions. In another aspect, it relates to articles of manufacture wherein at least a portion of the surface is coated with this strippable wax composition.

Strippable coatings are well-known in the art. They are utilized in applications wherein it is desirable to provide temporary surface protection against abrasion, rust, dirt and other damage occurring in storage and handling. After the necessary protection period has expired, it is desirable that these coatings be removed with a minimum of time and effort. These requirements have led to the development of various compositions which may be deposited as coatings upon a surface and thereafter removed as essentially continuous films. For example, polyvinyl chloride plastisols can be deposited, cured, and then peeled from a surface. This coating is very expensive and therefore, can only be economically deposited in thickness of a few mils. Furthermore, a strippable coating is produced only after the liquid plastisol has been properly cured at temperatures in the order of 300 F.

In order to eliminate the necessity of a cure, hot melt coatings have been produced from cellulosic materials such as ethyl cellulose in combination with large proportions of mineral oil. These compositions usually are quite odorous, have oily surface appearances and require coating temperatures in excess of 300 F. Other hot melt coatings such as those made from wax alone are not strip pable. The addition of various polymers including ethylene-vinyl acetate copolymers imparts physical strength to the wax film but it also increases the adhesive bond between the surface and the film. In order to impart strippability, various additives such as mineral oil, fluorinated compounds, silicones and partial esters have been incorporated into these wax-polymer compositions. These additives either impart high cost, poor coating appearance or necessitate extensive coating techniques.

It has now been found that outstanding strippable coatings can be produced by combining wax with ethylene-vinyl acetate copolymers and minor amounts of certain nitrogen-containing compounds. These compositions offer excellent strippability, low cost and they do not require complex coating processes. The coating compositions of this invention can be economically applied in considerable thicknesses using a hot melt technique without need of any subsequent cure.

The compositions of this invention may be used to protect the surfaces of metals such as aluminum, steel, zinc, brass, and chromium or the surfaces of various plastic or 3,518,215 Patented June 30, 1970 synthetic products such as laminates of phenol-formaldehyde, melamine-formaldehyde and urea formaldehyde resins, phonograph records, and the surfaces of many natural products such as wood paneling, flooring strips and the like. In general, the compositions of this invention may be utilized on any solid surface, such as glass, ceramic or mica, which forms a minimum adhesive bond with the coating.

It is an object of this invention. to provide wax compositions which may be deposited upon a surface and thereafter completely removed from the surface as essentially continuous films.

It is a further object of this invention to provide articles of manufacture which have these strippable wax com positions deposited upon their surfaces.

The compositions of this invention comprise in parts by weight:

-(A) parts of wax; and (B) from 10 to 300 parts of a polymeric composition consisting essentially of:

(i) from 40-100 weight percent of an ethylenevinyl acetate copolymer having a vinyl acetate content ranging from 15-35 weight percent, and

(ii) from 060 weight percent of a plasticizer for the ethylene-vinyl acetate copolymer,

(C) In an amount sufficient to impart strippability at least one compound selected from the group consisting of (i) an N-substitnted fatty acid amide (ii) an N-alkoxylated amine containing a fatty residue.

(D) from 0 to 20 parts of a hydrocarbon oil having a viscosity at 210 F. in excess of 25' SSU.

The N-substituted fatty acid amides and the N-alkoxylated amines hereafter described broadly amides or amines must be present in the compositions within a certain critical concentration range. The concentration must be suflicient to impart strippability without completely destroying the bond between the surface and the coating. In order to be considered strippable, it is necessary that the coating be capable of being totally removed from the surface as essentially continuous films. These critical amines or amide concentrations are dependent upon the type of amine or amide utilized, the type and amount of other components present, and the degree of strippability desired. In most compositions, strippability is obtained with amine or amide concentrations as low as 0.5 part by weight in 100 parts Wax. Concentrations which range from 1 to 5 parts by weight per 100 parts wax have been found to be most satisfactory. Higher concentrations, while operable, are accompanied by substantial amine or amide migration to the surface of the coating. The extent of this migration varies with the par ticular amine or amide and in general is related to its wax compatibility. This migration may totally destroy the adhesive bond, or provide an unattractive coating appearance and feel.

The N-substituted fatty acid amides which can be utilized in the practice of this invention have the following structural formula:

wherein M is hydrogen or an alkali metal having an atomic numbers of less than 20. Preferably M is hydrogen or sodium and most preferably, it is hydrogen. n is an integer from 14 and preferably is 1. R is hydrogen or an alkyl group containing 1-4 carbon atoms preferably methyl. R is an aliphatic radical containing to carbon atoms, and can be saturated or unsaturated, and linear or branched chain. It can be derived from the hydrocarbon residues of monocarboxylic fatty acids. These hydrocarbon residues can be substituted with a pendant oxygen atom such as a keto or hydroxyl group or an ester linkage. Suitable hydrocarbon residues which can be utilized include but are not limited to the residues derived from saturated acids such as n-undecyclic, lauric, myristic, n-pentadecyclic, palmitic, margaric, stearic, avachidic, behenic, lignoceric, cerotic, n-heptacosoic and nhentriacontoic; unsaturated acids such as the mono-ethenoid, caproleic, 10-decyler1ic, lauroleic, palmitoleic, oleic, elaidic, erucic, selacholeic and lumegueic acids; the polyethanoid acids such as linolelaidic, eleostearic, punicic, linolenic and moroetic acids; substituted acids such as ricinoleic, lanoceric and licanic acids; branched chain acids such as Z-methyldodecanoic, 14-ethyl hexadecanoic, 18-n-propyl heneicosanoic, Z-methyl tetracosanic, 9-octyl heptadecanoic, 3,3-dime thyloctadecanoic and 2,9-dimethyloctadecanoic acids. Preferably R is a linear, aliphatic radical containing 10 to 17 carbon atoms. Most preferably, R is the hydrocarbon residue derived from stearic acid and has the formula (C H The following specific N-substituted fatty acid amides are illustrative of the different types which can be utilized in the compositions of this invention.

N-butyLN- Z-carboxyethyl -6-octyl-9-dodecenamide N-methyLN- (4carboxybutyl -octadecanamide N-'( 3-carb oxypropyl) -2,7-dimethyl-3 1 O-octacosadienamide N-ethyl,N-(4-carboxybutyl) -12-n-hexy1 octadecanamide N-methyl,N- 2-carboxyethyl -dodecanarnide N- S-carboxypentyl) -3 ,9-diethyl-tetradecanamide N-ethyl-N- S-carboxypentyl -2,6,8-tripropylundecanamide N-rnethyl,N- Z-carboxyethyl -octademanamide N-ethyLN- 3-carboxypropyl -heptadecanamide N-butyl,N- 3-carboxypropyl -undecanarnide N-propyl,N- 3-carboxypropyl -octadecanamide N-propyLN- 2-carboxyethyl -hexadecanamide N-butyl,N- 4-carboxybutyl -pentadecanamide N-butyl,N- 3-carboxypropyl -4,7,7-trimethylundecanamide N-butyl,N- 4-carboxybutyl -hexacosanamide N- 3-carboxypropyl) -triacontanamide N-(2-carboxyethyl)-10-decenamide N-methyl,N- 2-carboxyethyl -9-octadecenamide N-propyl,N- S-carboxypentyl) -21-triacontenamide N-ethyl,N-(Z-carboxyethyl)-12,14-dimethyl-9-hexadecenamide N- 3-carboxypropyl 15 -pentyl-9-eicosenamide N-methyLN-(Z-carboxyethyl)-9,12-octadecadienamide N-ethyl,N- (3-carboxypropyl -9,1 1,13-octadecatrien amide N-methyLN- Z-carboxyethyl -9-dodecenamide N-methyl,N- 2-carboxyethyl -6-octadecenamide N-propyLN-(.S-carboxypentyl)-4,8,12,15,18,21-

tetracosahexaenamide N-butyl,N-(3-carboxypropyl)-12-hexy1-6,10-hexadecadienamide N-propyLN-(4-carboxybutyl)-6,14-dibuty1-9- octadecenamide N-ethyl,N- 2-carboxyethyl -9-octadecynamide N-methyLN- (Z-carboxyethyl) -12-hydroxy-9-octadecenami'de N-(Z-carboxyethyl)-4-oxo-9,11,13-0ctadecatrienamide N-methyl,N-(2-carboxyethyl)-16-hydroxy-hexadecanamide and the sodium, potassium or lithium salts thereof.

The preparation of these amides is not critical to the practice of this invenion. For example, these compounds can be prepared by replacing the hydroxyl group of an wherein Z is a radical selected from the group consisting of Preferably Z is (R), or (RCO) and most preferably is (R). R is an aliphatic radical containing 103() carbon atoms and can be saturated or unsaturated, linear or branched chain, and can be substituted with a pendant oxygen atom such as a keto or hydroxy group or an ester linkage. It can be derived from the hydrocarbon residues of monocarboxylic fatty acids. Examples of monocarboxylic acids whose hydrocarbon residues can be utilized were heretofore set forth in the discussion of the N-substituted fatty acid amides. Preferably, R is a linear aliphatic radical containing 1017 carbon atoms. Most preferably, R is a mixture of the hydrocarbon residues derived from tallow which contains approximately 25 percent by weight palmitic acid, 35 percent by weight stearic acid and 45 percent by weight oleic acid. The hydrocarbon residues of other naturally occurring fatty acid mixtures such as coconut oil and soybean oil can be utilized. 1 is an integer from 1-6 and preferably is 3. W is selected from the group consisting of hydrogen and a lower alkyl radical containing up to about 6 carbon atoms. Preferably it is hydrogen. X represents the alkoxylated portion of the molecule and is a radical having the structural formula:

wherein R" is a methyl, ethyl or hydrogen radical; R' is a methyl or hydrogen radical; n and n" are the corresponding integers which define an alkoxy radical having from 1-4 carbon atoms derived from aldehyde, oxirane, oxetane or tetrahydrofuran compounds. n can range from 0-4, and n" can range from 02. The following table defines the R" and R' radicals corresponding to various combinations of integers possible within the maximum four carbon atom limit.

Preferably, the alkoxy radical is derived from ethylene oxide or propylene oxide. Most preferably, it is derived from ethylene oxide.

The alkoxy chains which are included in the above formula include the methoxy chain; chains derived from 1,2-epoxides such as ethylene, propylene, butylene, and isobutylene oxides; chains derived from the 1,3-epoxides ,;;:,such as 1,3-propylene, butylene, and isobutylene oxides;

chains derived from the 2,3-epoxides such as 2,3-butylene oxide; and chains derived from the 1,4-epoxide such as tetrahydrofuran.

In general, the length of the alkoxy chain as defined by y, y and v is determined by its molecular weight. It has been found that the marginal strippability is attained when the molecular weight of each alkoxy chain defined by y and y exceeds 1320 or when the molecular weight of the alkoxy chain defined by v exceeds 220. It is also critical that the compound contain at least one alkoxy radical bonded to the nitrogen atom. Therefore, with respect to these limitations the value of y can range from 1 to the quotient of 1320 divided by the molecular weight of X and the value of y can range from zero to the quotient of 1320 divided by the molecular weight of X. The value of v ranges from zero to the quotient of 220 divided by the molecular weight of X. Preferably, the alkoxy chains y and y are substantially equal in length. Preferably, y and y range from 1-5 and v ranges from 1-3. Most preferably, y, y and v are each 1.

The range of values of y, y and v for the designated alkoxy radical is set forth in Table B. The maximum values were calculated from the formulae: y or y"=1320 divided by the molecular weight of X; v=220 divided by the molecular weight of X. These maximum values were calculated for chains wherein a single type of alkoxy radical was utilized. However, individual chains having mixtures of the various alkoxy radicals can be prepared and the maximum values of y, y and v determined after defining the actual number of each type of alkoxy radical present in the chain.

TABLE B Where the alky is an integer y is an integer 11 is an integer oxy radical 1sranglng fromranging from-- ranging from- Methoxy 1-44 -44 0-14 Eth0xy 1-30 0-30 0-10 Propoxy-.. 1-22 0-22 0-7 Butoxy 1-18 0-18 0-6 Specific alkoxylated compounds wherein Z is equal to, (R) include but are not limited to:

N-ethoxy-dodecanamide N,N-di (polyethoxy) -octadecanamide N,N-di(polyethoxy)-9,12-octadecadienamide 6 N,N-di(polyethoxy)-9,12,15-octadecatrienamide N,N-di(poly-1,2-propoxy)-6, l2-dipenty1-9-tetradecanamide N,N-di(poly-1,3-propoxy) -18-isobutyl-tetracosanamide N,N-di (polyethoxy) -hexadecanamide N,N-di(po1yisobutoxy) -2-isopropyl--lZ-tridecenamide N, N-di poly- 1,4-butoxy) -6,9-dihydroxy-tetradecanamide N- (poly-2,3 -butoxy) -7,9-dioxo-S-hydroxy-pentadecanamide N,N-di (ethoxy) -octadecanamide N,N-di [poly (2,3-butoxyethoxy) ]-eicosanamide N,N-di [poly( 1,3-propoxy-1,2-prop0Xy) -12-hexadecynamide N,N-di (polymethoxy) -2,4, 8-trimethyl-tetradecanamide Specific alkoxylated compounds wherein Z is [RNCH2]t ]l [XlvW include but are not limited to:

N-(6-aminohexy)-N,N',N-tri(poly-1,2-pr0poxy)-4,8-

diethyloctanediamine N- (3 -aminopropyl) -N,N'-di (poly-2,3-butoxy) -9 hexadecenediamine N- (4-arninobutyl) -N,N-di (poly-1,4-butoxy -hexadecane diamine -N-(3-aminopropyl) -N,N',N'-tri(poly-1,3-propoxy)-8,12-

dihydroxyhexadecane diamine N- 3-aminopropyl) -N,N,N'-tri (polyethoxy) -4-oxo-1 1- tetradecene diamine -N- (Z-aminoethyl-N- (poly-1,2-propoxy) -N'- (poly-2,3-

butoxy) -N'- (poly ethoxy) -3,6,S-trimethyl-tetradecane diamine N-(aminomethyl -n,n-di (polyethoxy) -12-tetradecene diamine N- (S-aminopentyl) -N,N',N'-tri (polymethoxy) -octadecane diamine N-(3-aminopropyl)-N,N,N'-tri(polyethoxy)-bctadecane diamine N-(4-aminobutyl) -N,N',N'-tri (poly-1,3-propoxy) -9,12-

octadecadiene diamine N-(S-aminopentyl)-N,N',N'-tri(polyethoxy)-4,8,12,15-

octadecatetraenoic diamine N- (aminomethyl) -N,N',N'-tri (polyisobutoxy) -6-methy1- octadecene diamine N-(Z-aminomethyl)-N',N-di(poly-1,2-propoxy)-octadecane diamine N-(6-aminohexy)-N,N',N'-tri(poly-1,4-butoxy)-9- octadecyne diamine N- (4-aminobutyl) -N,N,N-tri(polyethoxy) -14-pentylheptadecane diamine N-(3-aminopropyl)-N,N',N'-tri(polyethoxy)-octacosane diamine N- 3-aminoprophyl) -N,N,N'-tri ethoxy -hexadecane diamine N- (3-aminopropyl) -N,N,N'-tri (propoxy-1,3 -octadecane diamine.

The preparation of the N-alkoxylated amine is not critical to the practice of this invention. For example, compounds wherein Z is (R) can be prepared by reacting a primary amine having the formula (R--NH with alkylene oxide. Compounds wherein Z is (RCO) can be prepared by alkoxylating the amide of the corresponding fatty acid. Compounds wherein Z is -R-N-(cH2)tcan be prepared by reacting an N-aliphatic alkylene diamine having the formula (RNH(CH NH with an alkylene oxide.

In the above alkoxylatcd compounds wherein it is desirable to utilize the methoxy linkage, it is necessary to first react the amine with at least one molecule of ethylene oxide or a higher alkylene oxide to establish a basic medium for the propagation of the methoxy group. Once this basic medium has been established, formaldehyde or its dimers and trimers may be reacted to promulgate the methoxylated chain. It is necessary, however, to cap these methoxylated chains in order to provide stability. This requires that the terminal hydrogen on each methoxy chain be removed and replaced by any suitable capping radical. For example, the terminal OH group can be esterified with methyl iodine to form a (OCH group.

The wax component of this invention can be any wax which can be deposited upon a surface as a molten or solvent cut coating and thereafter changed into a solid phase by cooling or by evaporation of the solvent. These waxes can be of mineral, vegetable, animal or synthetic origin. Mixtures of various waxes can also be utilized. Exemplary of waxes having a mineral origin are the petroleum and hydrocarbon waxes such as paraflin, microcrystalline, slack, ozocerite and montan waxes. Waxes having a vegetable origin are carnauba, candelilla, Japan waxes and the like. Waxes having an animal origin include bees, Chinese, insect and similar waxes. In the animal and vegetable waxes the main constituents are high molecular weight esters and saturated hydrocarbons and lesser amounts of alcohols and acids. Exemplary of the synthetic waxes include those produced by the esterification of polyhydric alcohols or by the hydrogenation of vegetable oils or those made by the Fischer-Tropsch synthesis or substituted waxes such as oxidized or chlorinated polyethylene wax.

The use of petroleum waxes represents a preferred embodiment of this invention. These waxes include paraffin waxes which have a melting point from about 115 F. to about 200 F. and the microcrystalline waxes having a melting point from about 140 F. to 210 F. These waxes may be fully refined and thus contain very small amounts of hydrocarbon oils or they may be semirefined (slack waxes) and have hydrocarbon oil contents of up to about 30 percent. As more fully discussed hereafter, oils of this type may be added to the compositions of this invention to enhance the strippability of the coating in amounts ranging up to percent of the total composition. Therefore, in determining an upper oil loading, the amount which is present due to the addition of a semirefined wax should be included.

The most preferred compositions of this invention utilize 100 percent by weight microcrystalline wax having a melting point ranging from 140 F. to 210 F. or a combination of petroleum waxes comprising from 20 to 80 percent by weight of a paraffin wax having a melting point ranging from about 120 F. to about 180 F. and from 80 to 20 percent of microcrystalline wax having a melting range from about 140 F. to about 210 F. This wax mixture provides strippable coating which can be utilized in high temperature applications. Increasing the concentration of microcrystalline wax will impart a higher maximum use temperature and improve the ultimate physical strength while decreasing dimensional stability. With respect to parafiin waxes as a class the use of a non-normal paraffin wax imparts higher physical strength than the normal base paraffin waxes.

The copolymers which can be utilized in the practice of this invention are solid thermoplastic polymers produced by polymerizing a major amount of ethylene with a minor amount of vinyl acetate. These copolymers should be solid at ambient temperatures (i.e. 70 F.) and have a molecular weight sufiicient to impart film strength without requiring excessive copolymer concentrations. The molecular weight can be further defined through the term melt index as determined by AST M D 123862. In general, the operable copolymers have melt indexes of less than 500. Preferably, the melt index is less than and most preferably, less than 5. Co polymers having melt indices as low as .5 have been prepared in the laboratory and have been found to impart outstanding strength characteristics. The vinyl acetate concentration in the copolymers can range from 15 to 35 percent by weight. The higher concentration defines the practical limits of copolymer compatibility with the wax. Copolymers having a vinyl acetate content of less than 15 percent are more compatible but excessive copolymer concentrations are necessary to impart the desired film properties. The optimum film properties are obtained with copolymers having a vinyl acetate concentration ranging from 25 to 30 weight percent and are therefore preferred in the compositions of this invention.

The ethylene-vinyl acetate copolymers can be utilized in the practice of this invention alone or in conjunction with a compound which is a plasticizer for the copolymer. Exemplary compounds which are recognized as plasticizers for ethylene-vinyl acetate copolymers include but are not limited to monomeric plasticizers such as dioctyl adipate, dioctyl phthalate, butyl phthalyl glycollate and aceto tributyl citrate or higher molecular weight plasticizers such as hydrocarbon oils, polyterpenes, polybutenes, epoxidized soy bean oil, coumarone-indene resins, polystyrene and organic carboxylic acids. These plasticizers in general have molecular weights of less than 3,000, are compatible with wax at the blending and application temperatures and have boiling or degradation temperatures which are higher than the temperatures incurred during coating. The coumarone-indene resins represent a preferred class of plasticizers. They are prepared by the catalytic polymerization of coal-tar, light-oil fractions boiling between 150 C. and 200 C. This fraction is commonly called crude heavy solvent and contains primarily indene, styrene, cyclopentadiene and their methyl homologs and minor amounts of coumarone. These resins have a softening point of less than C. as determined by the ring and ball method described in ASTM Test Number D-36-62T. Preferably, this softening point is less than 50 C.

The use of organic carboxylic acids as plasticizers for the ethylene-vinyl acetate copolymers also represents a preferred embodiment in this invention. This carboxylic acid must be wax compatible, have an acid number in excess of about 20 and a molecular weight ranging from to 3,000. Preferably, the acid number is in excess of 30. Compounds with low acid numbers and high molecular weights, i.e., oxidized polyethylene are not desirable because they increase the viscosity of the molten composition without imparting the desired properties. Any aliphatic, acyclic or aromatic acid having one or more carboxyl groups can be utilized. For example, dimerized and trimerized fatty acids, rosin acids and naphthoic acids can be also utilized.

The ethylene-vinyl acetate copolymer should be utilized in amounts sufficient to impart physical strength to the coatings thus allowing them to be stripped from the surface as essentially continuous films. This requires a proper balance between the adhesive and cohesive forces with the adhesive force being less than the cohesive force. As the concentration of copolymer is increased, the physical strength of film is also increased. However, accompanying this improvement, is an increase in melt viscosity and in processing and material costs. Therefore, from both economic and processing viewpoints, the copolymer concentration should be the optimum required to impart the necessary strippability. A portion of the ethylenevinyl acetate copolymer can be replaced by the plasticizers heretofore described. This copolymer-plasticizer mixture is hereafter described in the specification and claims as the polycomposition. This composition consists essentially of from 40 to 100 percent by weight of an ethylene vinyl acetate copolymer and from 0 to 60 percent by weight plasticizer. Most preferably, the plasticizer concentration ranges from 5 to 30 percent. The amount of polymeric composition which can be utilized in the compositions of this invention can range in amounts from 10 parts to 300 parts by weight of wax. Therefore, the copolymer can range in concentrations of from 4 to 300 parts per 100 parts of wax, and the plasticizer concentration can range from to 180 parts per 100 parts wax. When the maximum plasticized concentration of 180 parts is utilized, the maximum copolymer concentration is 120 parts. The most preferred concentration of polymeric composition ranges from 20 to 110 parts per 100 parts of wax.

As previously stated, a hydrocarbon oil can be added to the composition of this invention to aid in strippability, impart a plasticizing effect and lower the hot melt viscosity. This hydrocarbon oil has a viscosity at 210 F. of greater than 25 SSU and preferably from about 35 to about 500 SSU at 210 F. A preferred oil is a highly refined n-parafiin petroleum oil having a viscosity of from 43 to 45 SSU at 210 F. The oils can be incorporated into the compositions of this invention in amounts ranging up to about 20 parts per 100 parts wax, however, excessive oil loading will greatly reduce tensile strength. Preferably the oil concentration ranges up to about 15 parts and most preferably from 1 to parts. As previously stated, some petroleum waxes commonly known as semi-refined waxes contain substantial amounts of oil. When these semi-refined waxes are utilized in this invention, its oil content should be taken into account in determining the maximum or optimum oil loading. In determining the amount of wax present for the purposes of defining a common parts basis, the inherent oil content of semi-refined wax should be excluded.

Ingredients commonly added to wax or ethylene-vinyl acetate copolymers can be incorporated into the compositions of this invention in functional amounts without departing from the scope thereof. Examples of these ingredients include but are not limited to: heat and ultraviolet light stabilizers, inert fillers, secondary plasticizers, anti-blocking agents, pigments and colorants, anti-oxidants, gloss stabilizers, viscosity-index improvers, solvents, anti-scuff agents, etc.

The preparation of the compositions of this invention is not critical to the practice thereof and can be conducted under any suitable method. For example, these compositions can be prepared by heating the wax to a temperature above its melting point, adding the ethylenevinyl acetate copolymer, release agent and other additives and agitating vigorously until a homogeneous hot melt is obtained.

When a plasticizer is utilized, it is preferable to incorporate the plasticizer into the melted wax prior to the addition of the copolymer in order to facilitate the dispersion of the copolymer. Similarly, a coating composition can be prepared by combining ingredients with a common solvent. A specific method for preparation is as follows: The waxes are melted together, any anti-oxidents or heat stabilizers are added and the melt is then brought to a temperature above about 275 F. The plasticizer, if it is not free flowing, is heated to about 275 F. and then added to the hot melt. The ethylene-vinyl acetate copolymer is then added to the melt accompanied by vigorous stirring while maintaining the melt temperature above about 275 F. After all of the copolymer has been added, the melt temperature is raised to about 300 F. and agitated until the copolymer and resins are completely dispersed. The desired release agents are then added.

Articles of manufacture can be prepared in any manner which results in a deposition of coating on its surface. For example, the articles may be dipped in a hot melt and cooled to allow the coating to solidify. This coating can also be deposited utilizing common coating processes such as curtain coating, roll coating and spray coating. The same technique is followed when the solvent wax system is utilized. After coating, the solvent is evaporated. These coatings may be applied in any thickness. However, it is necessary that the thickness provide sufficient strength in the film to allow the film to remain intact during stripping. Normally, coating thicknesses greater than 1 mil. have this requisite strength.

The following examples are givein to illustrate the preferred embodiments of this invention and should not be construed as limitations upon the invention. All parts are by weight.

EXAMPLE I The waxes of Table I were melted together and raised to a temperature of 300 F. The coumarone-indene resin was heated to 275 F. and then added to the hot melt. The ethylenevinyl acetate copolymer was then added to the melt with constant and vigorous agitation while maintaining a melt temperature above 275 F. The melt temperature was raised to 300 F. after all of the copolymer had been added and maintained at that temperature for approximately minutes until all of the copolymer had dissolved. The melt temperature was. then lowered to 280 F. and the various release agents were added. The hot melt was deposited with a coating bar as 1 to 5 mil. coatings on the surfaces of melamine-formaldehyde plaques. The coating was allowed to cool to room tem perature and after a 24 hours period, its strippability was evaluated. With other plaques, immediately after the coating was cooled, it was reheated to 170 F. for 10 minutes and allowed to cool. After 24 hours at ambient temperatures, strippability was evaluated. The results are reported in 4 different categories:

Excellent (-E) is used to designate a coating which could be easily and rapidly removed as a single continuous film. Good (G) denotes a coating which could be easily removed without the application of excessive force. However, at faster stripping rates it had a propensity to tear in random fashion along the direction of the force and thus was removed as several large pieces. Fair (F) designates a coating which could be stripped only by apply ing excessive force. Slow removal rates were necessary and even then it come off in the form of small random pieces. Poor (P) denotes a coating which had high adhesion requiring the application of excessive force at very slow removal rates. Small random pieces were obtained under these conditions. Not Strippable (N.S.) means that the coating did not exhibit any stripping characteristics.

1 The wax was a blend or 70.5 parts microcrystalline wax having a melting point of 175 F. (ASTM D-127) and 29.5 parts of a fully refined paraffin wax having a melting point ranging from 150 to 155 F. (AS'IM D-87). Both waxes had an oil content of less than 1 percent.

2 An ethylene-vinyl acetate copolymer having a bound vinyl-acetate go rli tent of 28 percent by weight and a melt index of 3.0 (ASTM D1238 3 Coumarone-indene resin having a ring and ball softening point of 38 C. (ASTM D-36-627).

4 A solvent refined hydrocarbon oil comprised mainly of n-paralfins lgvging a viscosity index of to and a viscosity at 210 F. of 43-46 5 With reference to the general formula set forth in the specification, the oleo sarcosine is defined as follows: R is the fatty residue oleic acid, R is methyl, 1 is 1, M is hydrogen. It was prepared by reacting oleic acid chloride with n-methyl amino acetic acid, ester and then saponiiying the product to the acid.

Table I demonstrates that the addition of an N-substituted fatty acid amide to the prior art compositions greatly enhances the strippability. By comparing Formulation 3 with 2, it is demonstrated that even higher amounts of the prior art stripping agents (oil) will not impart this outstanding strippability.

EXAMPLE 2 13 Formulations 15-48 set forth in Table III demonstrate various specific embodiments of this invention. Formulation, 19 is a prior art composition which does not have satisfactory strippability.

EXAMPLE IV In order to demonstrate the effect of plasticizers, blends containing:

100 parts wax 81.8 parts ethylene-vinyl acetate copolymer 45.5 parts plasticizer were prepared in accordance with the method set forth in Example I. The wax component contained 25 percent by weight microcystalline wax having a melting point of 175 F. (ASTM D-127 and 75 percent by weight of a paraffin wax having a melting point of 135 F. (ASTM D-87). The ethylene-vinyl acetate copolymer 28 percent by weight bound vinyl acetate and has a melt index of 3.0 (ASTM D-1238-57T).

The various plasticizers and their evaluations are set forth in Table IV.

CH2CH2OH 20 wherein R is the hyrocarhon group derived from the fatty acids found in tallow.

TABLE IV Formulation Number Coumnrone in- Epoxitlized 4 soy- Plasticizer Poiyterpene 1 dene resin 8 Dioctyl adipato Dioctyl phthaiate been oil Polybutene 5 Hot melt viscosity at 300 F. (GP). 6, 425 6, 300 3, 350 4, 280 5, 760 4, 250 Elongation, percent 1 105 166 36 45 33 Energy absorption 1 factor, ft.-lbs./in. 25. 4 52. 2 4. 4 i2. 6 15. 1 10 I Microtensile method AS'IM D-1708-59T. 1,000, a sponification number of 181 and an absolute viscosity at 20 C.

I A terpene resin having a ring and ball softening point of 55 C. (ASTM of 516 centipoises.

3 As definedin footnote Table I. 4 An epoxidized soybean oil having an average molecular weight of The energy absorption factor is the area under the curve obtained by plotting the force applied on the composition (stress) against its resulting elongation (strain). Thus, the higher energy absorption factors described compositions which in the presence of a release agent can be readily stripped without tearing. In this regard, the composition plasticized with the coumarone-indene resin has 40 5 A butene homoplymer having an average molecular weight of 700, and a viscosity at 210 F. of 11,000 SSU.

References Cited UNITED STATES PATENTS 3,306,882 2/ 1967 Pullen. 3,268,466 8/1966 McAninch. 3,207,716 8/ 1965 Lippoldt. 3,108,981 10/1963 Clark. 3,104,232 9/ 1963 Clark. 2,991,265 7/1961 Clark. 2,956,979 10/ 1960 Rowland. 3,427,265 2/ 1969 Brinker.

MORRIS LIEBMAN, Primary Examiner P. R. MICHL, Assistant Examiner U.S. Cl. X.R.

vinyl acetate copolymer wherein the vinyl ace- 26032.6 

